Fault diagnosis system and method of exhaust gas temperature sensor of hybrid vehicle

Abstract

An exhaust temperature sensor fault diagnosis method of a hybrid vehicle includes: determining whether a starting of the vehicle is turned on depending on an operation of a starter switch; determining whether a fault diagnosis condition of the exhaust temperature sensor is satisfied; diagnosing the fault of the exhaust temperature sensor if the fault diagnosis condition of the exhaust temperature sensor is satisfied; determining whether the engine is driving during the fault of the exhaust temperature sensor is diagnosed; and finishing the fault diagnosis of the exhaust temperature sensor if the engine is not driving.

What is claimed is: 
     
         1 . An exhaust temperature sensor fault diagnosis method of a hybrid vehicle comprising:
 determining whether a starting of the vehicle is turned on depending on an operation of a starter switch;   determining whether a fault diagnosis condition of the exhaust temperature sensor is satisfied;   diagnosing the fault of the exhaust temperature sensor when the fault diagnosis condition of the exhaust temperature sensor is satisfied;   determining whether an engine is driving during the fault of the exhaust temperature sensor is diagnosed; and   finishing the fault diagnosis of the exhaust temperature sensor when the engine is not driving.   
     
     
         2 . The exhaust temperature sensor fault diagnosis method of  claim 1 , wherein the fault diagnosis condition of the exhaust temperature sensor is satisfied when a driving time of the engine exceeds a predetermined driving time, an exhaust temperature exceeds a predetermined temperature, and the exhaust temperature lasts during a predetermined time that the exhaust temperature exceeds the predetermined temperature. 
     
     
         3 . The exhaust temperature sensor fault diagnosis method of  claim 2 , wherein a fault in a power line of the exhaust temperature sensor is diagnosed when an output voltage of the exhaust temperature sensor exceeds an uppermost predetermined value, and
 a fault in a ground line of the exhaust temperature sensor is diagnosed when the output voltage of the exhaust temperature sensor is smaller than a lowermost predetermined value.   
     
     
         4 . The exhaust temperature sensor fault diagnosis method of  claim 1 , wherein the fault diagnosis condition of the exhaust temperature sensor is satisfied when a driving time of the engine exceeds a predetermined driving time and an exhaust temperature is smaller than a threshold temperature. 
     
     
         5 . The exhaust temperature sensor fault diagnosis method of  claim 4 , wherein the fault of the exhaust temperature sensor is diagnosed when the driving time of the engine exceeds the predetermined driving time and the exhaust temperature is smaller than the threshold temperature. 
     
     
         6 . The exhaust temperature sensor fault diagnosis method of  claim 2  or  claim 4 , wherein when an accumulation fuel injection amount reaches a predetermined value, it is determined that the driving time of the engine exceeds the predetermined driving time. 
     
     
         7 . An exhaust temperature sensor fault diagnosis system of a hybrid vehicle comprising:
 an exhaust pipe in which an exhaust gas exhausted from engine flows;   a SCR catalyst installed at the exhaust pipe and configured to reduce a nitrogen oxide included in the exhaust gas;   an exhaust temperature sensor installed at a previous stage of the SCR catalyst and configured to measure an exhaust temperature; and   a controller configured to determine a fault of the exhaust temperature sensor when a fault diagnosis condition of the exhaust temperature sensor is satisfied.   
     
     
         8 . The exhaust temperature sensor fault diagnosis system of  claim 7 , wherein the controller determines whether the fault diagnosis condition of the exhaust temperature sensor is satisfied when a driving time of an engine exceeds a predetermined driving time, the exhaust temperature exceeds a predetermined temperature, and the exhaust temperature lasts during a predetermined time that the exhaust temperature exceeds the predetermined temperature. 
     
     
         9 . The exhaust temperature sensor fault diagnosis system of  claim 8 , wherein the controller diagnoses that a fault is generated in a power line of the exhaust temperature sensor when an output voltage of the exhaust temperature sensor exceeds an uppermost predetermined value, and diagnoses that an fault is generated in a ground line of the exhaust temperature sensor when the output voltage of the exhaust temperature sensor is smaller than a lowermost predetermined value. 
     
     
         10 . The exhaust temperature sensor fault diagnosis system of  claim 7 , wherein the controller determines that the fault diagnosis condition of the exhaust temperature sensor is satisfied when a driving time of an engine exceeds a predetermined driving time and the exhaust temperature is smaller than a threshold temperature. 
     
     
         11 . The exhaust temperature sensor fault diagnosis system of  claim 10 , wherein the controller diagnoses the fault of the exhaust temperature sensor when the driving time of the engine exceeds the predetermined driving time and the exhaust temperature is smaller than the threshold temperature.